# Structures, phase transitions, and magnetic properties of Co3Si from first-principles calculations

## TL;DR

This study uses first-principles calculations to explore the crystal structures, phase transitions, and magnetic properties of Co3Si, revealing new stable phases and insights into its magnetic behavior.

## Contribution

It provides a comprehensive first-principles analysis of Co3Si's structures and magnetic properties, identifying the most stable phases and their magnetic states.

## Key findings

- Hexagonal Co3Si is non-magnetic and less stable at zero temperature.
- The ferromagnetic hexagonal structure is dynamically unstable.
- An orthorhombic structure is more stable and has the lowest energy.

## Abstract

Co3Si was recently reported to exhibit remarkable magnetic properties in the nanoparticle form [Appl. Phys. Lett. 108, 152406 (2016)], yet better understanding of this material is to be promoted. Here we report a study on the crystal structures of Co3Si using adaptive genetic algorithm, and discuss its electronic and magnetic properties from first-principles calculations. Several competing phases of Co3Si have been revealed from our calculations. We show that the hexagonal Co3Si structure reported in experiments has lower energy in non-magnetic state than ferromagnetic state at zero temperature. The ferromagnetic state of the hexagonal structure is dynamically unstable with imaginary phonon modes and transforms to a new orthorhombic structure, which is confirmed by our structure searches to have the lowest energy for both Co3Si and Co3Ge. Magnetic properties of the experimental hexagonal structure and the lowest-energy structures obtained from our structure searches are investigated in detail.

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Source: https://tomesphere.com/paper/1704.04514